<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    nav {
      width: 100%;
      height: 50px;
      background-color: #333;
    }
    
    ul {
      list-style: none;
      margin: 0;
      padding: 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      height: 100%;
    }
    
    li {
      position: relative;
      z-index: 1;
    }
    
    a {
      color: #fff;
      text-decoration: none;
      padding: 10px;
    }
    
    a::before {
      content: '';
      position: absolute;
      top: -5px;
      bottom: -5px;
      left: -5px;
      right: -5px;
      z-index: -1;
      background-color: #fff;
      transform: skew(-10deg);
    }
  </style>
</head>

<body>
  <nav>
    <ul>
      <li><a href="#">Home</a></li>
      <li><a href="#">About Us</a></li>
      <li><a href="#">Services</a></li>
      <li><a href="#">Contact</a></li>
    </ul>
  </nav>
</body>

</html>